Battery charger



FIG. 1 is a perspective view of a battery charger showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a side view thereof; and,

FIG. 7 is the opposite side view of FIG. 6 thereof. 

The ornamental design for a battery charger, as shown and described. 